Protein drugs represent a group of the most effective and the fastest growing medicines, used to treat various severe chronicle conditions such as cancer, diabetes, hepatitis, leukemia and rheumatoid arthritis. A critical problem in protein therapy is that most protein drugs are currently administered by daily or multiple weekly injections. Such frequent injections have resulted in poor patient compliance and require frequent nurse visits. A formulation technology that is broadly applicable to all proteins for a long-term dosing will dramatically increase patient compliance, thus better clinical outcome, and reduce the overall medical cost from less health care provider visits. Erythropoietin (EPO) is chosen as the target to develop long-acting formulation technology in the proposed research because of its important medical and commercial significance. EPO, a glycoprotein produced by the kidney, helps to increase body's natural production of red cells and is thus used in the treatment for chronic renal failure and cancer chemotherapy. It is the protein drug having largest global market and patient population. Though a sustained-release formulation for therapeutic proteins has been eagerly sought by leading pharmaceutical and biotechnology companies, achieving this goal has proven to be a daunting task, with little success to date. Proteins are easily denatured in formulation processes and prolonged in vivo release from injected dosage forms. The most challenging part in developing sustained release protein products is to achieve protein stability, a linear prolonged release profile and formulation simplicity simultaneously. In the present study, this problem will be addressed using our unique patented formulation method involving a stable aqueous-aqueous polysaccharide emulsion and hydrophilic oil/oil microencapsulation. Initial application of our formulation technology (using only FDA approved injectable ingredients) to EPO indicates that the protein can be slowly released with prolonged in vivo efficacy for 4 weeks after a single injection. In this Phase I research, this sustained-release EPO formulation will be optimized for pre-clinical and clinical trials. [unreadable] [unreadable] PUBLIC HEALTH RELEVANCE: While proteins represent a group of the most effective and the fastest growing medicines used to treat various severe chronicle conditions, frequent injections, the standard dosage regime for this type of drugs, have resulted in poor patient compliance and frequent nurse visits. Based on initial success on EPO, a protein drug for treatment of renal failure and cancer, the proposed research is aimed to develop a new protein dosage form that offers a month-long efficacy by a single injection. [unreadable] [unreadable] [unreadable]